The present invention relates to expansion clamps and, more particularly, to an expansion clamp for use with a resilient tubular gasket or boot to provide a leakproof joint in a piping system.
Clamps used for the repair of pipe leaks at a joint or elsewhere are well known in the art. Generally these clamps are applied to the external pipe surface in the vicinity of the leak to effectively prevent the pressurized pipe contents from escaping. However, frequently a repair or connection must be made to a pipe which is buried having therefore an inaccessible external surface. Thus, internal expansion clamps have been devised to provide a method of repairing the pipe from the inside thereof. Frequently these pipes have relatively large internal diameters, e.g., a sewer waste line, where the repair connection thereto is made via a resilient gasket or rubber boot which is affixed to the internal surface of a sewer pipe by means of an expansion clamp being expanded to supply the necessary compressive forces and then locked into position. The expansion clamp also may be used to secure a rubber boot in a sewer manhole inlet opening to effect a seal so that when the other end of the boot is attached to the inlet pipe a sealed, leakproof joint is obtained.
Presently used expansion clamps generally include radially internally extending protrusions which are adjusted until the expansion clamp sufficiently expands to tightly engage the inner surface of a pipe section or joint thereby effecting a leakproof seal. Some of the other known expansion clamps include a multiplicity of elements and require elaborate and tedious installation procedures.